Spark plug socket for internal combustion engines

ABSTRACT

A socket element for insertion of a spark plug has a central bore of triangular cross-section, receiving an ignition circuit conductor in tangential relation as to all three sides. The remaining cavities are filled with elastomeric filler material to seal the conductor as well as a resistor and the socket contact in the interior of the bore.

United States Patent 1191 Loy Oct. 21, 1975 SPARK PLUG SOCKET FOR INTERNAL 2,488,065 11/1949 Peterson 339/136 C X OM T O ENGINES 2,666,423 1/1954 Johnson 339/136 C X 3,803,529 4/1974 Rohrig' 339/26 [75] Inventor: Fritz Loy, l-leroldsberg, Germany [73] Assignee: Kabel-und Metallwerke Gutehoffnungshutte AG, l-lannover, Primary Examiner-Joseph McGlynn Germany Assistant Examiner-Howard N. Goldberg 1 Filed: J 1974 Attorney, Agent, or Firm-Ralf H. Siegemund [21] Appl. No.: 431,594

[30] Foreign Application Priority Data [57] ABSTRACT Dec. 14, 1972 Germany 2261103 A socket element for insertion of a spark plug has a [52] US. Cl. 339/26; 339/136 C; 339/213 3 central bore of triangular cross-section, receiving an [51] Im. C1. 1-l0lR 13/52 ignition circuit con uctor n tangential relation as to [58] Field of Se hu 339/26, 60 C, 136 C, 143 3 all three sides. The remaining cavities are filled with 339/149 S, 213 S, 218 S; 425/129 elastomeric filler material to seal the conductor as well as a resistor and the socket contact in the interior 6] References Cited of the bore.

UNITED STATES PATENTS 2,458,121 2 Claims, 4 Drawing Figures 1 1/1949 Waldron 339/143 S liiilw s 2 A nk SPARK PLUG SOCKET FOR INTERNAL COMBUSTION ENGINES BACKGROUND OF THE INVENTION The present invention relates to a socket for a spark plug for internal combustion engines which socket connects to the end of an electric conductor or lead of the electrical ignition circuit.

Sockets of this type are known in various configurations and are made almost always from thermosetting material. These sockets are usually sufficiently strong, but they are also relatively brittle and break rather easily particularly because of the direct engagement of contacts, resistor and socket body. Additionally, it has to be observed that gaps appear between the rather stiff socket and the inserted conductor, so that moisture can creep into the interior of the socket, and leakage current will flow tending to destroy the socket. Additionally, the conductor can easily break at the opening and entrance into the socket.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a spark plug socket which protects its interior against moisture and protects the incoming conductor against breaking. I

In accordance with the preferred embodiment of the invention, it is suggested to provide a body-made of thermosetting plastic with a central, polygonal bore for receiving a conductor, i.e. an ignition lead in tangentially engaging relation as to the bore walls; the bore has an internal portion, which is defined by closed wall structure corresponding to the polygonal cross-section, the bore being filled with elastomeric plastic, filling all cavities between socket and conductor. In the preferred form, the polygon is to be a triangle as sufficiently large cavities are established between such a bore and a (round) conductor to obtain positively adequate quantities of filling material. One could also use a bore with rectangular cross-section, but a triangular cross-section provides for larger internal engaging surfaces between the body and the filler. A polygon with still more sides is less advantageous.

Since the bore is to have polygonal cross-section the conductor is automatically centered in the bore and in the socket as a whole. Additionally, upon filling the cavities in the socket with elastomeric plastic, one obtains a large area of contact for fixing the position of the conductor in the bore, so that any additional tension relief is not needed. The elastomeric filler obviates also the danger of breaking of the conductor at the entrance opening to the socket. This is particularly so if the entrance portion of the bore is widened to some extent so that the lead is clearly surrounded by an annulus, even an annular bead for sealing the bore and for providing relief against breaking of the lead upon bending.

DESCRIPTION OF THE DRAWINGS While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention, it is believed that the invention, the objects and features of the invention and further objects, features and advantages thereof will be better understood from the following description taken in connection with the accompanying drawings in which:

FIG. 1 shows a longitudinal section through a spark plug socket in accordance withthe preferred embodiment of the invention;

FIG. 2 is a section along lines 11-" in FIG. 1;

FIG. 3 shows a longitudinal section through a spark plug socket in accordance with another example of the preferred embodiment of the invention; and

FIG. 4 is a section along lines IVIV in FIG. 3.

Preceeding now to the detailed description of the drawings, FIG. 1 illustrates a socket member or body 1 made of thermosetting plastic and having a longitudinal, centrally located bore 2 of triangular cross-section. An ignition wire or lead spark of a plug cable 3 is inserted into the bore in that the round lead has tangential disposition to all three sides of the triangle. Accordingly, the round lead 3 is centered in the bore in that it is received in an elongated cavity of triangular crosssection and having three straight and flat uninterrupted walls; particularly in the internal regions of the bore.

The conductor or lead 3 does not penetrate the bore in its entirety but connects to a resistor 4, contained also in the bore, which in turn is connected to a contact element 5 in the bottom of the opening, which will receive theplug end of a spark plug 6.

After parts 4 and 5 have been placed into the bore 2, and after lead 3 has been inserted and the appropriate electrical connections have been made, all remaining cavities are filled with elastomeric plastic which, upon curing, will constitute the coherent tiller 7.

Filler 7 is in intimate contact with the three straight and flat walls of bore 2, (i.e. with the socket member 1 as such) as well as with the parts 3 and 4, firmly embedding them in bore 2 in centered position. The area of bonding contact between filler 7 and member 1 is rather large due to the triangular configuration. The

entrance opening of bore 2 is widened to obtain a.

closed annulus of elastomeric material surrounding conductor and sealing off the interior of bore 2. The elastomeric filler projects somewhat from this opening and provides support and relief against severe local bending of the lead. Additionally, and as shown also in the upper portion of FIG. 1, lateral bores in element 1 will also fill with elastomeric material upon injection thereof, to form anchoring lugs 8, preventing any longitudinal displacement of the filler 7 in bore 2.

It may be necessary in some cases to shield the socket for eliminating h.f. interference. FIGS. 3 and 4 show a basically similar socket but received in a metallic sleeve 9. The sleeve is rather loosely placed onto and around socket element 1. However, element 1 is provided with longitudinal, possibly rather shallow grooves 10 on the outside; the cavities resulting from the shield covering the grooves are also filled with elastomeric material.

As can be seen from the upper portion of FIG. 3, the inner tiller 7 is, in effect extended around the entrance opening for the conductor lead 3, forming a head 12 from which extends filler material into the grooves 10 for positioning element 1 inside of sleeve 9. Bead 12 provides improved sealing of the interior of socket element 1, as well as improved protection against breaking of the lead 3, should it be bent. Another'bead 11 at the opposite end of the socket member seals the socket against the spark plug itself.

The invention is not limited to the embodiments described above, but all changes and modifications thereof not constituting departures from the spirit and scope of the invention are intended to be included.

I claim: 1;Socket for spark plugs for internal combustion engines, comprising a single piece socket member of elongated configuration having connection means at one end for receiving a spark plug, and being made of thermosetting plastic, themember having a central longitudinal bore, the bore having three sides integrally connected together so that said bore will have an uninterrupted periphery defined by said sides, said bore will thus have a cross-section defined by a triangle, the bore being closed except at the other end, the bore receiving at the other end a round conductor lead in tangentially abutting relationship as to each of the three sides of the bore, the three. sides of the bore thus centering the lead through said abutting relationship, the bore having a wider portion at the other end, terminating inan opening through which passes the inserted conductor lead,

receiving thevmember and elastomeric filler material in the grooves and being integral with the filling material in said spaces. 

1. Socket for spark plugs for internal combustion engines, comprising a single piece socket member of elongated configuration having connection means at one end for receiving a spark plug, and being made of thermosetting plastic, the member having a central longitudinal bore, The bore having three sides integrally connected together so that said bore will have an uninterrupted periphery defined by said sides, said bore will thus have a cross-section defined by a triangle, the bore being closed except at the other end, the bore receiving at the other end a round conductor lead in tangentially abutting relationship as to each of the three sides of the bore, the three sides of the bore thus centering the lead through said abutting relationship, the bore having a wider portion at the other end, terminating in an opening through which passes the inserted conductor lead, said lead having one end thereof adapted for connection to said connection means so that the socket is an end socket for said conductor lead; and elastomeric filler material for filling the remaining spaces between the conductor lead and the three sides of said bore for positioning the conductor lead in embedding relationship in the bore, and annularly sealing the conductor at said opening and other end.
 2. Socket element as in claim 1, and having longitudinal grooves on the outside, a metallic shielding sleeve receiving the member and elastomeric filler material in the grooves and being integral with the filling material in said spaces. 